Dissolved oxygen shimmer is a one-dimensional microprobe technique for realizing detection of dissolved oxygen concentration at a certain point in the sludge-water interface. It is an optical fiber information exchange sensor based on a fluorescence quenching principle; since oxygen is a natural quencher for some fluorescent indicators, oxygen-sensitive fluorescent indicators are made into oxygen sensing membranes coupled to the end part of the optical fiber; high-brightness light-emitting diodes are used as a light source and miniature photodiode detection system, the oxygen concentration is determined by the optical fiber-conducting fluorescence quenching intensity; a ruthenium complex, with the characteristics of insensitivity to stirring and resistance to the interference of H2S, CO2 and salinity, is so far the most widely used oxygen-sensitive fluorescent indicator.
A current method for the dissolved oxygen determination in the sludge-water interface comprises the following steps: taking a sample of the sludge-water interface from the water area to be detected into a detection container, then fixing a dissolved oxygen shimmer probe on the upper portion of the container, and controlling a fluorescent probe tips on the probe to downwardly extend into the sludge-water interface for determination.
This method has the following disadvantages:                1. The detection range is small, which means that only the data of dissolved oxygen about the sludge-water interface around the dissolved oxygen shimmer probe can be collected at one time;        2. In-situ determination cannot be achieved, but rather, samples of the sludge-water interface need to be taken into the detection container, which can easily lead to changes in the natural environment around the sludge-water interface, resulting in inconsistence of the dissolved oxygen situation of the sampled sludge-water interface with the actual situation;        3. Only one dissolved oxygen shimmer probe can be controlled to detect the dissolved oxygen situation of one position at a certain height in the sludge-water interface each time; the dissolved oxygen situation of the position at other heights or the dissolved oxygen situations of other positions at the same height can only be detected by multiple-time detection which, however, takes a larger time span, may not reflect the real situation; and        4. The height of the probe to the sludge-water interface needs to be controlled by mechanical operation which will easily get damaged, causing time-and-effort consuming operation and inconvenient detection.        